ask your gp for steroid injections around the lump, i have finished a course of 3 injections, each one 3 months apart, the difference is huge. my plantar was painful, right on the arch of my foot, causing pain when walking and wearing some shoes, now it has more than halved in size and no pain! i have to wait another 9 months before i can go back for more sessions.
hope this is a help to other sufferers.
richard.